drivers/thermal/spear_thermal.c

   1 /*
   2  * SPEAr thermal driver.
   3  *
   4  * Copyright (C) 2011-2012 ST Microelectronics
   5  * Author: Vincenzo Frascino <vincenzo.frascino@st.com>
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #include <linux/clk.h>
  19 #include <linux/device.h>
  20 #include <linux/err.h>
  21 #include <linux/io.h>
  22 #include <linux/kernel.h>
  23 #include <linux/of.h>
  24 #include <linux/module.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/thermal.h>
  27
  28 #define MD_FACTOR       1000
  29
  30 /* SPEAr Thermal Sensor Dev Structure */
  31 struct spear_thermal_dev {
  32         /* pointer to base address of the thermal sensor */
  33         void __iomem *thermal_base;
  34         /* clk structure */
  35         struct clk *clk;
  36         /* pointer to thermal flags */
  37         unsigned int flags;
  38 };
  39
  40 static inline int thermal_get_temp(struct thermal_zone_device *thermal,
  41                                 unsigned long *temp)
  42 {
  43         struct spear_thermal_dev *stdev = thermal->devdata;
  44
  45         /*
  46          * Data are ready to be read after 628 usec from POWERDOWN signal
  47          * (PDN) = 1
  48          */
  49         *temp = (readl_relaxed(stdev->thermal_base) & 0x7F) * MD_FACTOR;
  50         return 0;
  51 }
  52
  53 static struct thermal_zone_device_ops ops = {
  54         .get_temp = thermal_get_temp,
  55 };
  56
  57 #ifdef CONFIG_PM
  58 static int spear_thermal_suspend(struct device *dev)
  59 {
  60         struct platform_device *pdev = to_platform_device(dev);
  61         struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
  62         struct spear_thermal_dev *stdev = spear_thermal->devdata;
  63         unsigned int actual_mask = 0;
  64
  65         /* Disable SPEAr Thermal Sensor */
  66         actual_mask = readl_relaxed(stdev->thermal_base);
  67         writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
  68
  69         clk_disable(stdev->clk);
  70         dev_info(dev, "Suspended.\n");
  71
  72         return 0;
  73 }
  74
  75 static int spear_thermal_resume(struct device *dev)
  76 {
  77         struct platform_device *pdev = to_platform_device(dev);
  78         struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
  79         struct spear_thermal_dev *stdev = spear_thermal->devdata;
  80         unsigned int actual_mask = 0;
  81         int ret = 0;
  82
  83         ret = clk_enable(stdev->clk);
  84         if (ret) {
  85                 dev_err(&pdev->dev, "Can't enable clock\n");
  86                 return ret;
  87         }
  88
  89         /* Enable SPEAr Thermal Sensor */
  90         actual_mask = readl_relaxed(stdev->thermal_base);
  91         writel_relaxed(actual_mask | stdev->flags, stdev->thermal_base);
  92
  93         dev_info(dev, "Resumed.\n");
  94
  95         return 0;
  96 }
  97 #endif
  98
  99 static SIMPLE_DEV_PM_OPS(spear_thermal_pm_ops, spear_thermal_suspend,
 100                 spear_thermal_resume);
 101
 102 static int spear_thermal_probe(struct platform_device *pdev)
 103 {
 104         struct thermal_zone_device *spear_thermal = NULL;
 105         struct spear_thermal_dev *stdev;
 106         struct device_node *np = pdev->dev.of_node;
 107         struct resource *res;
 108         int ret = 0, val;
 109
 110         if (!np || !of_property_read_u32(np, "st,thermal-flags", &val)) {
 111                 dev_err(&pdev->dev, "Failed: DT Pdata not passed\n");
 112                 return -EINVAL;
 113         }
 114
 115         stdev = devm_kzalloc(&pdev->dev, sizeof(*stdev), GFP_KERNEL);
 116         if (!stdev)
 117                 return -ENOMEM;
 118
 119         /* Enable thermal sensor */
 120         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 121         stdev->thermal_base = devm_ioremap_resource(&pdev->dev, res);
 122         if (IS_ERR(stdev->thermal_base))
 123                 return PTR_ERR(stdev->thermal_base);
 124
 125         stdev->clk = devm_clk_get(&pdev->dev, NULL);
 126         if (IS_ERR(stdev->clk)) {
 127                 dev_err(&pdev->dev, "Can't get clock\n");
 128                 return PTR_ERR(stdev->clk);
 129         }
 130
 131         ret = clk_enable(stdev->clk);
 132         if (ret) {
 133                 dev_err(&pdev->dev, "Can't enable clock\n");
 134                 return ret;
 135         }
 136
 137         stdev->flags = val;
 138         writel_relaxed(stdev->flags, stdev->thermal_base);
 139
 140         spear_thermal = thermal_zone_device_register("spear_thermal", 0, 0,
 141                                 stdev, &ops, NULL, 0, 0);
 142         if (IS_ERR(spear_thermal)) {
 143                 dev_err(&pdev->dev, "thermal zone device is NULL\n");
 144                 ret = PTR_ERR(spear_thermal);
 145                 goto disable_clk;
 146         }
 147
 148         platform_set_drvdata(pdev, spear_thermal);
 149
 150         dev_info(&spear_thermal->device, "Thermal Sensor Loaded at: 0x%p.\n",
 151                         stdev->thermal_base);
 152
 153         return 0;
 154
 155 disable_clk:
 156         clk_disable(stdev->clk);
 157
 158         return ret;
 159 }
 160
 161 static int spear_thermal_exit(struct platform_device *pdev)
 162 {
 163         unsigned int actual_mask = 0;
 164         struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
 165         struct spear_thermal_dev *stdev = spear_thermal->devdata;
 166
 167         thermal_zone_device_unregister(spear_thermal);
 168
 169         /* Disable SPEAr Thermal Sensor */
 170         actual_mask = readl_relaxed(stdev->thermal_base);
 171         writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
 172
 173         clk_disable(stdev->clk);
 174
 175         return 0;
 176 }
 177
 178 static const struct of_device_id spear_thermal_id_table[] = {
 179         { .compatible = "st,thermal-spear1340" },
 180         {}
 181 };
 182 MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
 183
 184 static struct platform_driver spear_thermal_driver = {
 185         .probe = spear_thermal_probe,
 186         .remove = spear_thermal_exit,
 187         .driver = {
 188                 .name = "spear_thermal",
 189                 .pm = &spear_thermal_pm_ops,
 190                 .of_match_table = spear_thermal_id_table,
 191         },
 192 };
 193
 194 module_platform_driver(spear_thermal_driver);
 195
 196 MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
 197 MODULE_DESCRIPTION("SPEAr thermal driver");
 198 MODULE_LICENSE("GPL");